METHOD AND APPARATUS FOR DIGESTION TREATMENT OF ORGANIC WASTE

摘要

PROBLEM TO BE SOLVED: To stably perform digestion treatment for forming biogas from organic waste. SOLUTION: A weir 19 is disposed at the position near to the inlet 2 of a push-out flow type digestion tank 1 having the inlet 2 at one end part thereof and having an outlet 3 at the other end thereof and the section on the upstream side of the weir 19 is set as a first chamber 20 provided with a sample collection port 33. The weir 19 is equipped with a fixed plate provided with an opening part and a slide plate provided with an opening part and both plates are slid to open and close the opening parts. A digested sludge return line 21 for guiding a part of digested sludge 11 discharged from the outlet 3 is connected to the first chamber 20. Organic waste 4 is charged in the first chamber 20 in such a state that the weir 19 is closed to be subjected to acid fermentation and, when the concentration of free propionic acid exceeds 50 mg/L, the digested sludge 11 is returned to the first chamber 20 by a predetermined volume to reduce the concentration of free propionic acid to 50 mg/L or less and the weir 19 is opened to allow organic waste 4 to flow downstream to subject the same to methane fermentation.